Why does the property I want to mock need to be virtual?

Question

I\'m doing some unit testing, and mocking some properties using Moq.

Now, this is a Controller test (ASP.NET MVC 3). My Controllers

Answer 1

Moq and other similar mocking frameworks can only mock interfaces, abstract methods/properties (on abstract classes) or virtual methods/properties on concrete classes.

This is because it generates a proxy that will implement the interface or create a derived class that overrides those overrideable methods in order to intercept calls.